In the prior art, a back plate for a heat dissipator is a rectangular metal plate with threaded holes at its four corners. The threaded holes of the back plate correspond to the threaded holes of a motherboard, and can be fixed to each other with screws.
There is an improved back plate, which has multiple oval or gourd-shaped threaded holes at each corner, so it can fit different motherboards with different threaded hole arrangements. However, the producing cost of this type of back plate is high. In addition, the multiple threaded holes at each corner reduce the structural strength, and the oval or gourd-shaped holes have less stability while being connected. Furthermore, the screws are disposed through the threaded holes from the front side of the motherboard, but the back plate is disposed at the back side of the motherboard, so the sight of the assembler is blocked by the motherboard while aligning the threaded holes, which makes it difficult to assemble the back plate.
Moreover, there is a back plate assembly, which consists of two pieces of metal plates. The metal plates form in a cross shape, and each end of the metal plates has a long narrow opening for a locking member to slide over so that the back plate assembly is able to fit the motherboards with different threaded hole arrangements. However, the structural strength of the back plate assembly is low, so the back plate assembly is unable to bear large amounts of stress. The producing cost of this type of the back plate assembly is high as well.